The following U.S. patents and other publications are believed to have possible relevance to the subject matter of the present invention: U.S. Pat. Nos. 6,041,183; 6,029,068; 5,987,135; 5,936,860 & 5,900,870.
A detailed explanation of the difference between the present invention and applicant's own prior art, which is believed to be the closest prior art, is set forth hereinbelow in the Detailed Description of a Preferred Embodiment.